Drill



l Julyl 15 1924.

1501,0755 T. E. STURTEVANT DRILL Filed Dec. 17, 1919 Patented July l5, 1924.

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THOIMAS E. STURTEVANT, OF DOVER, JERSEY, ASSGNOR TO MCKIERNAN-TERRY DRILL COMPANY, OF DOVER, NEV JERSEY, .A CORPORATION OF NEW JERSEY.

DRILL.

Application filed December 17, 1919. Serial No. 345,520.

To all wlw/m t may concern.'

Be it known that I, THOMAS E. STURTE- vANT, a citizen of the United States of America, and a resident of Dover, Morris County, and State. of New Jersey, have invented cert-ain new and useful Improvements in Drills, of which the following is a specification.

. My present invention relates to drills of the so-called hammer type in which the drill steel is partially rotated on each return stroke of the hammer or piston.

In drills of this type, as heretofore constructed, pawl and ratchet mechanism have been provided permitting the drill to turn on the retracting stroke and to hold the drill against rotation on its forward or active stroke. This mechanism is necessarily subjected to great vibration and, as heretofore constructed, is liable to breakage and wears out quite rapidly with use.

The objects of this invention are to improve the ratchet mechanism to enable it to withstand the hard usage to which it is subjected and to construct the parts so that the pawls may be interchangeably used until practically entirely worn out.

To these ends the yinvention involves a number of novel features, combinations and arrangements of parts, as set forth inthe following specification, reference being had to the drawing accompanying and forming a part thereof, and in which I have illust-rated the invention embodied in a simple and practical form. y

In the drawing, Figure 1 is a vertical sectional view of a rotary hammer drill of improved construction and having my invention incorporated therein. This view is taken substantially on the plane of the line 1---1 of Figure 2.

Figure 2 is an enlarged horizont-al sectional view, as taken substantially on the plane of the line 2--2 of Figure 1.

Figure 8 is a det-ached perspective view of the pawl carrying head.

The drill illustrated in Figure 1 consists of the usual cylinder 5 and the piston 6 operating therein, and connected with the socket member 7 for a drill steel 8.

A partial rotary movement is imparted to the piston on the up stroke thereof by means of the usual rifle bar 9 which takes into a socket 10 in the piston.

rlhis rifle bar at its upper end isy formed into or provided with a pawl carrying head 11 and surrounding this head is a ratchet ring 12 having the internal teeth or shoulders 13 for engagement with the pavvls now to be described.

These pawls are designated 14, and in this particular instance, are shown as two in number, one disposed at each side of the pawl carrying head. Said pawls are of novel construction being formed in each instance, as a rectangular parallelopiped having eight similar edges or pawl faces 15 equal in length and capable of being used interchangeably.

Sockets for the pawls are provided in the opposite sides of the pawl carrying head. These sockets are open to the side of the head throughout a large portion of their eX- tent, so as to permit one end of the pawl to swing outwardly into engagement with the ratchet teeth, and may be formed by simply milling Vor otherwise cutting slots in the sides of the head. The pawlseats are shown Aformed with a plane back' wall 16 disposed substantially as a chord of the circular head, an end wall 17 at the forward' or open end of the seat and disposed substantially at a right angle to the back wall, and an abutment wall 18 at the opposite inner or rearward end of the seat disposed on an angle oblique to the back wall. Extending from the outer end of this obliquely disposed abutment wall is a hook-like projection or extension 19 overstanding the socket at this end and forming the same into a pocket to receiveV and hold the inner or pivot end of the pawl. It will be noted in Figure 2 that the oblique angle of the abutment wall 18 corresponds to the angle at which the inner end of the pawl stands when the outer end thereof is seated against a ratchet tooth, so

that said wall provides a continuous support for the rear abutment edge of the pawl.

The pawls in the illustration are pressed outwardly by the spring actuated plungers 20, which are seated in suitable bores in the head. 'v

VThe mechanism illustrated is of simple and at the same time very sturdy construction. The parts are few and not liable to get out of order. The wear at the abutment end of the pawls is distributed across the entire rear face of the pawl and the pawls are interchangeably engageable in their seats in eight different ways, so that eight different pawl Y faces may be brought into position for operative engagement with the shoulders of the ratchet member. In addition to the advan tagesenumerated, the structure is relatively inexpensive involving only simple machining operations. The form of pawl element disclosed also has the advantage that it can be easily tempered Without fear of breakage and all the various faces thereof can on account kof its uniformity of shape be brought to practically the same degree of hardness. l-Vhat I claim is:

l. Rotating mechanism for hammer drills, comprising 'in combination with a ratchet ing, of a paWl carrying rhead rotatable Within said ring and provided With a seat in one side thereof, a pawl loosely fitting in said seat, a shoulder at one edge of the seat overstanding one end of the pawl to prevent outward displacement of the adjacent end of the pawl, and means at the other edge of the seat serving to guide the adjacent end of the pawl outwardly into engagement with the teeth of the. surrounding ring.

2. Rotating mechanism for hammer drills, coinprising in con'ibination, an internal ratchet member, a head rotatable in said memberand provided with a. pawl seat in one side thereof open to the side of the head at one end and having a hooked projection overstanding the opposite end portion thereof, a pawl in said seat having one end thereof engaged beneath the projection aforesaid, and means intermediate the pavvl urging the free end of the same toward the ratchet member. l

3. Rotating mechanism for hammer drills, comprising in combination a member having internal kratchet teeth, a paWl carrying head rotatably mounted in said member and provided With a parvl seat in one side thereof open to the side of the head at the forward end thereof, a stop shoulder at said forward end of the seat and a hooked projection partially closing the rear end of the seat, and a paivl having one end confined to the seat by the hooked projection, the other end of the pawl being movable toward and away from the ratchet teeth and guided in such movement bythe stop shoulder aforesaid.

4. In rotating mechanism for hammer drills, a paivl carrying head having a paWl seat formed in the side thereof, said paivl seat having a plane 4back Wall disposed as a chord of the head, a rear end Wall disposed atan oblique angle to said back Wall, and a front end Wall disposed substantially at a right angle to the back Wall, and a substantially rectangular pawl disposed in saidseat and arranged to engage said Walls.

5. In rotating mechanism for hammer drills, a paivl carrying head having a pawl seat formed in the side thereof, said pawl seat havinga! plane back Wall disposed as a chord of the head, a rear end Wall disposed at an oblique angle to said back Wall, and a front end Wall disposed substantially at a right angle to the back Wall, a substantially rectangular paWl disposed in said seat and arranged to engage said Walls, and a shoulder extending substantially at a right angle fro-1n the obliquely disposed end Wall and overstanding one end of the pavvl.

6. In rotating mechanism for hammer drills, a pawl carrying head having a. paWl seat formed in the side thereof, said pawl seat having a plane back Wall disposed as a cho-rd of the head, a rear end Wall disposed at an oblique angle to said back Wall, and a front end Wall disposed substantially at a right angle to the back Wall, and a substantially rectangular paivl disposed in said seat and arranged to engage said Walls, said paWl being interchangeably engageable in said seat.

7. In rotating mechanism for hammer drills, a pawl carrying head havingA a pawl seat formed in 'the side thereof, said pawlseat having a plane back Wall disposed as a chord of the head, a rear end Wall disposed at an oblique angle to said back Wall, and a front end Wall disposed substantially at a right angle to the back Wall, a substantially rectangular pawl disposed in said seat and arranged to engage said Walls, and a shoulder extending substantially at a right angle from the obliquely disposed end wall and overstanding one end of the pawl, the pavvl being interchangeably engageable with the seat described.

8. In rotating mechanism for hammer drills, a paivl carrying head having a paivl seat formed in the side thereof, said pawl seat havingA a plane back Wall disposed as a chord of the head, a rear end Wall disposed at an oblique angle to said back Wall, and a front end Wall disposed substantially at a right angle to the back Wall, and a substantially7 rectangular paivl disposed in said seat and arranged to engage said Walls, said pawl being in the form of a parallelopiped.

9. In rotating mechanism for hammer drills, a pawl carrying head having a socket arranged to receive a paWl and a paWl in the form of a parallelopied having eight edges of equal length and arranged to be used interchangeably as pa-Wl faces, said pavvl being laterally movable in the socket and said head having an extension limiting the lateral paWl movement.

10. In rotating mechanism for hammer drills, a4 pavvl carrying head having av socket arranged to receive a paWl and a pawl in the form of a parallelopiped having a plurality of interchangeably movable faces and being laterally movable in said socket, said head having' means engageable With the paWl for limiting the lateral-movement thereof.

l1. Rotating mechanism for hammer drills, comprising in combination With an internal ratchet, of a pawl carrying head rotatably disposed in said ratchet and provided with open sockets in opposite sides thereof, said sockets each having a stop shoulder at one end and an over-standing lug at the opposite end thereof, and a pawl interchangeably engaged in each socket and having one end thereof caught beneath the overstanding lug and the opposite end arranged to slide across the face of the stop shoulder.

12. Rotating mechanism for hammer drills, comprising an internal ratchet, a rotary pawl carrying head within said ratchet and provided with an open socket in one side thereof, and a lug overstanding one end portion of said socket, a pawl in said socket and engaged at one end beneath said overstanding lug, a spring pressed plunger in the head for swinging the opposite end of the pawl outwardly into engagement with the internal ratchet, and a stop shoulder on the head for engagement with the outward engaging end of the pawl to prevent a sliding movement of the pawl from beneath the overstanding lug.

13. Rotating mechanism 'for hammer drills, comprising an internal ratchet, a rotatable pawl-carrying head within said ratchet, a flat abutment in said head, a pawl fulcrumed insaid head and interposed bec tween said ratchet and abutment, that end of the pawl in engagement with the abutment being flat, the pawl in moving out of contact with the ratchet fulcruming on one of its face edges on the abutment.

1d. Rotating mechanism for hammer drills, comprising an internal ratchet, a rotatable pawl-carrying head within said ratchet, a flat abutment in said head, a pawl `interposed between said ratchet and abutratchet, a Hat abutment in said head, a pawl interposed between said ratchet and abut ment, that .end of the pawl in engagement with the abutment being flat, the pawl in moving out of contact with the ratchet fulcruming on that edge of its face nearest the axis of the pawl-carrying head.

16. Rotating mechanism for hammer drills, comprising an internal ratchet, a rotatable pawl-carrying head within said ratchet, a flat abutment in said head, a pawl in the form of a parallelopiped interposed between said ratchet and abutment, the pawl in moving out of contact with the ratchet fulcruming on one of its face edges on the abutment.

17. Rotating mechanism for hammer drills, comprising an internal ratchet, a rotatable pawl-carrying head within said ratchet, a at abutment in said head, a pawl fulcrumed in said head and interposed be tween said ratchet and abutment, that end of the pawl in engagement with the abutment being fiat, the pawl in moving out of contact with the ratchet fulcruming on one of its face edges on the abutment and the pawl-carrying head, the flat face of the abutment being disposed at right angles-*to the pawl when the pawl is in driving position with respect to the ratchet, whereby the driving pressure on the pawl acts at right angles to the plane of the flat abutment.

18. Rotating mechanism for hammer drills, comprising an internal ratchet, a rotatable pawl-carrying head within said ratchet, a flat abutment in said head, a pawl 'fulcrumedin said head and interposed between said ratchet and abutment, that cud of the pawl in engagement with the abutmen being flat, the pawl in moving out of contact with the ratchet fulcruming on one of its face edges on the abutment, the pawl in its active power transmitting position will be disposed at right angles to the plane of the abutment.

In witness whereof, I hereunto set my hand this 10th day of December, 1919.

THOMAS E. STURTEVANT. 

